fix: read a missing pgrep or ip as VPN down

scripts/lib/health.py

@@ -102,17 +102,29 @@ def send_html(self, html: str, status: int = 200) -> None:
 
 
 def _check_openvpn() -> bool:
-    """Check if at least one OpenVPN process is running."""
-    result = subprocess.run(["pgrep", "-x", "openvpn"], capture_output=True)
+    """Check if at least one OpenVPN process is running.
+
+    A host without pgrep reads as not running, so a /metrics scrape still answers.
+    """
+    try:
+        result = subprocess.run(["pgrep", "-x", "openvpn"], capture_output=True)
+    except FileNotFoundError:
+        return False
     return result.returncode == 0
 
 
 def _check_wireguard() -> bool:
-    """Check if wg0 interface exists and has a listening port."""
-    result = subprocess.run(
-        ["ip", "link", "show", "wg0"],
-        capture_output=True,
-    )
+    """Check if wg0 interface exists and has a listening port.
+
+    A host without iproute2 reads as no interface, so a /metrics scrape still answers.
+    """
+    try:
+        result = subprocess.run(
+            ["ip", "link", "show", "wg0"],
+            capture_output=True,
+        )
+    except FileNotFoundError:
+        return False
     return result.returncode == 0
 
 

tests/unit/test_health.py

@@ -118,6 +118,18 @@ def test_readiness_transitions(self, obs_server):
         assert status3 == 503
 
 
+class TestVpnChecksWithoutTheirTools:
+    """A host missing pgrep or iproute2 reads as VPN down, never an exception."""
+
+    @pytest.mark.parametrize("check", ["_check_openvpn", "_check_wireguard"])
+    def test_missing_binary_reads_as_down(self, monkeypatch, check):
+        def missing(*_args: Any, **_kwargs: Any) -> None:
+            raise FileNotFoundError(2, "No such file or directory")
+
+        monkeypatch.setattr(lib_health.subprocess, "run", missing)
+        assert getattr(lib_health, check)() is False
+
+
 class TestMetricsOnObservabilityPort:
     """A wired metrics object is served from the same port."""